A New Species of Hedruris (Nematoda: Hedruridae) from the Australian Skink Lampropholis guichenoti (Reptilia: Scincidae) Author(s): Hugh I. Jones and Julian Resasco Source: Comparative Parasitology, 83(2):173-177. Published By: The Helminthological Society of Washington DOI: http://dx.doi.org/10.1654/4806i.1 URL: http://www.bioone.org/doi/full/10.1654/4806i.1 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne s Terms of Use, available at www.bioone.org/page/ terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.
Comp. Parasitol. 83(2), 2016, pp. 173 177 A New Species of Hedruris (Nematoda: Hedruridae) from the Australian Skink Lampropholis guichenoti (Reptilia: Scincidae) HUGH I. JONES 1,3 AND JULIAN RESASCO 2 1 Microbiology, School of Pathology and Laboratory Medicine, M502, University of Western Australia, Nedlands WA 6009, Australia (e-mail: hugh.jones@uwa.edu.au) and 2 Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, Colorado, 80309 U.S.A. (e-mail: jresasco@colorado.edu) ABSTRACT: We describe a new species of Hedruris, Hedruris wogwogensis n. sp. (Nematoda), from the skink Lampropholis guichenoti in southeastern Australia. This nematode is distinguished from other species of Hedruris infecting reptiles principally by the extent of the rows of longitudinal scale-like bosses on the ventral surface of the male tail, which extend anteriorly for more than half the length of the worm. The species also differs in minor respects from other species of Hedruris, principally in its small size. KEY WORDS: Australia, Arcitalitrus, Hedruris, Lampropholis, Maxvachonia, Skrjabinodon, skink, nematode. The nematode genus Hedruris occurs in fish (Luque et al., 2010), amphibians (Petter, 1971), and reptiles (Bursey and Goldberg, 2000), primarily from damp or aquatic environments. Individual species of Hedruris are not known to develop in more than one class of vertebrates (Clark, 1978). They possess a number of characteristics that are unique to this genus (Chandler, 1919), the principal of which is a posterior sucker with an eversible hook at the enlarged posterior end of the female, by which the female attaches itself to the host stomach tissues. In an ecological study of the Australian skink Lampropholis guichenoti, J.R. found many preserved museum specimens to be infected with gastric nematodes, almost all of which we refer to the genus Hedruris. These differ from previously described species in this genus. MATERIALS AND METHODS One hundred and eighty-two Lampropholis guichenoti skinks were examined as part of an ecological study on habitat fragmentation. Skinks were collected as accidental bycatch in pitfall traps for arthropod collection in the Wog Wog Habitat Fragmental Experiment, NSW, Australia (37604930 S, 149628900 E; see Margules 1992 for study site description and methods) and are housed at the Australian National Wildlife Collection of the Commonwealth Scientific and Industrial Research Organization (CSIRO), Canberra, Australia. Nematodes and recovered and associated stomach contents were stored in 75% ethanol. Nematodes were cleaned, cleared in chlorolactophenol, and examined using a BA series Olympus microscope. Illustrations were made by the use of a drawing tube. All specimens have been returned to the collection at CSIRO. 3 Corresponding author. RESULTS Three species of nematode were recovered. One lizard contained a single female specimen of Skrjabinodon sp., in poor condition, and 1 lizard contained 3 female Maxvachonia chabaudi. An undescribed species of Hedruris occurred in 34/182 lizards (19 %), and we describe this new species below. Habronematoidea Hedruridae Railliet, 1916 Hedruris Nitzsch, 1821 Hedruris wogwogensis n. sp. Diagnosis With characters of the genus. Small nematodes, both sexes, 5.0 mm. Males with ca. 25 regular rows of small rectangular bosses or scales on ventral surface extending anteriorly from anus to more than half the length of the worm. Copulatory spicules curved ventrally about midlength, separate anteriorly, fused midlength, posterior end with membranous covering. Females markedly widened toward the posterior end, with large posterior ventral pouch in which stout hook is invaginated. Eggs simple, without lateral protuberances. Description (Figs. 1 9; Table 1) Two lateral pseudolabia and 2 median lips at anterior end of worm. Lateral pseudolabia thick, attached to body wall by stout narrow pedicle, with single small peg-like anteriorly directed papillae on dorsal and ventral margin and an amphid centrally. Dorsal and ventral lips triangular in outline, curved medially to partly enclose pseudolabia, and attached to body of 173
174 COMPARATIVE PARASITOLOGY, 83(2), JULY 2016 Figures 1 9. Hedruris wogwogensis n. sp. 1. Mature female nematode, lateral view, with terminal spine invaginated. 2. Anterior end, dorso-ventral view. 3. Anterior end, lateral view. 4. Anterior end, showing nerve ring, dereids, and excretory pore. 5. Female tail, lateral, with spine everted. 6. Male tail, ventro-lateral view. 7. Male copulatory spicule, ventral view. 8. Spine at posterior end of female. 9. Egg.
JONES AND RESASCO HEDRURIS IN AUSTRALIAN SKINKS 175 Table 1. Measurements of Hedruris wogwogensis n. sp. (length in mm, all other measurements in lm). Holotype Male paratype (3) Allotype Female paratypes (7) Length 4.78 4.00 5.10 4.70 3.1 4.7 Maximum width 120 140 480 400 510 Esophagus length 960 937 487 1080 660 920 Esophagus width 72 60 68 76 64 84 Nerve ring* 180 140 220 180 240 Excretory pore* 244 240 310 377 240 320 Dereid* 220 192 244 230 190 240 Tail 320 320 400 Spicule 172 140 180 Spine length 220 210 220 Eggs 67630 70630 56628 Ventral scales on male tail{ 52.3% 55% 65% * Distance from anterior end. { Distance from posterior end. worm by stout pedicle. Cuticle with pronounced deep transverse striations, especially in anterior portion. Buccal capsule short, leading to esophagus, flat anterior surface of which is cuticularized. Esophagus not visibly divided into muscular and glandular portions. Nerve ring surrounds esophagus near anterior end, and dereids at the same level. Excretory pore a short distance posterior to dereids. Male: Thin and of uniform width, tapering to a fine pointed tail. Curved ventrally, none in tight coils. Ventral surface of worm lined with 20 25 regular rows of longitudinally arranged rectangular bosses, extending anteriorly from immediately anterior to anus to slightly more than half length of worm. Tail with six pairs of papillae arranged on low subventral ridge, and 1 pair adanal, 1 pair immediately pre-anal, and 1 pair of small papillae on dorsolateral surface of tail. Copulatory spicules twisted longitudinally, well sclerotized, widely separated anteriorly, curved ventrally about midlength, becoming fused about midlength and separated again distally. Tips blunt, apposed, with fine membranous covering, just protruding from anal aperture in all specimens. Accessory piece not evident. Female: Approximately same length as males, width gradually increasing posteriorly so that posterior end 3 4 times width of that at esophago-intestinal junction. Posterior end rounded, curved dorsally, with voluminous cuticular bursa. Rim of bursa thick posteriorly, diminishing anteriorly, from which radiate very fine parallel lines on its internal surface. A large well-sclerotized eversible hook, with a stout peg on concave surface, articulates with the posterior rim of this bursa, and invaginates into a sac within the bursa. Anus and vulva on convex ventral surface of tail. Eggs elongate, without lateral swellings, thick smooth shells, operculate at both ends, embryonated. Taxonomic summary Type host: Lampropholis guichenoti (Duméril and Bibron, 1839). Type locality: Wog Wog Habitat Fragmentation Experiment, NSW, Australia (37604930 S, 149628900 E). Collection dates: January 1988, January 1989, April 1989, April 1990, February 1991, May 1991, October 1991, February 1992, May 1992, Oct 1992, February 1993, April 1993, October 1993, February 1994, April 1994, February 1995, April 1995, October 1995, February 1996, April 1996, April 1997. Site of infection: Stomach. Prevalence and intensity: Prevalence 34/182 skinks examined (19%). Intensity range 1 14 (mean, 5.3). Specimens deposited: Specimens deposited in the Australian National Wildlife Collection, Canberra, N5576 N5611. Specimens examined: 140 male and female adults (some incomplete). Etymology: wogwogensis from the collection sites of infected lizards in the Wog Wog Habitat Fragmentation Experiment, New South Wales, Australia. Remarks In most specimens examined the esophagus of the nematode was partly compressed longitudinally. This feature and the deep transverse cuticular striations suggest that many specimens were contracted, presumably resulting from their preservation, and thus the true lengths may be more than stated. The species of Hedruris described herein differs from all other species in a number of characteristics, principally size, morphology of eggs, number of caudal tubercles in males, and
176 COMPARATIVE PARASITOLOGY, 83(2), JULY 2016 the extent of the rectangular bosses on the ventral surface of the male. Six species have been described from reptiles. In Australia, Hedruris longispicula from the skink Lygosoma challengeri has a long and apparently simple spicule, almost as long as the tail, and the bosses on the male tail extend for most of the distance of the coils, though the distance is not stated (Thomas, 1959). Hedruris saltuarii from the Australian leaf-tailed gecko, Saltuarius moritzi, and Hedruris pendula from turtles in North America are both more than 20 mm in length; in the former there are 12 15 rows of bosses, and they extend anteriorly for 2.5 mm (ca. 15% of length of worm; Jones, 2013), and in the latter the flattened rectangular bosses on the ventral surface of the male tail extend as far as the beginning of the caudal coils and are in rows of 14 16 (Baker, 1986). Hedruris miyakoensis from the skink Scincella boettgeri in the Ryuku Archipelago, Japan, is also larger (ca. 9 mm), and the rows of rectangular bosses on the male tail extend as far as the first coils and the eggs are smaller (Hasegawa, 1989). The males of Hedruris hanleyae from the gecko Hemidactylus garnotti in the Cook Islands are only slightly larger but possess only 9 10 rows of rectangular bosses on the male tail, extending approximately 1.0 mm anteriorly (Bursey and Goldberg, 2000). Hedruris minuta from the skink Leiopisma smithi in New Zealand is the closest in size but bears more tubercles on the male tail, and the lines of bosses on the ventral surface of the male tail extend for only about one third of the length of the worm (Andrews, 1974). A single species (female only) has been recorded from an amphibian, Hyla jervisensis, in Australia (Johnston and Mawson, 1941). Thus in the species described herein, there are more rows of rectangular scales, and they extend further anteriorly than in other species for which these features are adequately described. Most descriptions state that the posterior part of the male is in about 3 tight coils (as was the case in H. saltuarii [Jones, 2013]), whereas males in this species were in semicircular or circular coils, never in tight spirals. This may be an artifact of preservation. Life cycles are known for 3 species of Hedruris; Hedruris androphora, fromthenewttriturus vulgaris in France, became adult in the body cavity of the isopod crustacean, Asellus aquaticus (Petter, 1971); Hedruris ijimai, from the frog Rana ornatoventris in Japan, develop in Asellus hilgendorfi (Hasegawa and Otsuru, 1979); and Hedruris spinigera in the amphipod Paracorophium excavatum (Luque et al., 2010). No life cycles are known from species of Hedruris that mature in reptiles. However, the terrestrial amphipod Arcitalitrus sylvaticus is abundant in Eucalypt forests of the Wog Wog Habitat Fragmentation Experiment (Margules et al., 1994) and could conceivably be an intermediate host for H. wogwogensis. Lampropholis guichenoti occurs in southeastern Australia, inhabiting wet and dry sclerophyll forests and moister woodlands and is common in suburban gardens (Cogger, 2014). No specimens of Hedruris have been recorded from the sympatric swampinhabiting skink Lissolepis coventryi (Jones and Watharow, 2010). Goldberg and Bursey (2012), in a review of helminths of Australian lizards, did not record Hedruris, or any other species of nematode, from L. guichenoti, nor have species of Hedruris been recorded in any species of skink or gecko from arid Australia (Jones, 1995). Further studies are needed to examine this nematode s life cycle and to determine whether it occurs in other species of skink. 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